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P R Wesselink - One of the best experts on this subject based on the ideXlab platform.

  • percentage of filled canal area in mandibular molars after conventional root canal instrumentation and after a noninstrumentation technique nit
    International Endodontic Journal, 2003
    Co-Authors: C N Ardila, P R Wesselink
    Abstract:

    Aim  To compare the percentage of filled canal area in mandibular molar roots after using conventional root-canal hand instrumentation or after a noninstrumentation technique (NIT). Methodology  Forty mandibular molars were used shortly after extraction. The root canals of 20 molars in the manual group were conventionally prepared using hand instruments and then filled with warm vertical compaction of gutta-percha. The 20 teeth in the second group were cleaned and obturated by NIT. In each case, the entire molar, including the crown and the roots, was embedded in an acrylic resin cylinder before NIT. Horizontal sections were cut at 2, 4, 6 and 8 mm from the apex. Images of the sections were taken using a microscope at ×40 magnification and a digital camera; the images were scanned as Tagged Image File Format (TIFF) images into a PC. The cross-sectional area of the canal with the filling materials was measured using an image Analysis Programme. The percentage of filled area was calculated. The difference in the percentage of filled canal area between the two groups was analysed using a Student's t-test. Results  At all levels, 93–100% of the canal area was filled in both groups. No significant difference was found between the manual technique and the NIT technique at any level (P > 0.05). Conclusions  Within the limitations of this study, following the cleaning and filling of root canals using NIT, the percentage of filled root canal was similar to that using warm vertical compaction of gutta-percha after conventional root-canal instrumentation.

Edgar Schafer - One of the best experts on this subject based on the ideXlab platform.

  • shaping ability of protaper next and bt race nickel titanium instruments in severely curved root canals
    International Endodontic Journal, 2015
    Co-Authors: Sebastian Burklein, D Mathey, Edgar Schafer
    Abstract:

    B€ S, Mathey D, Sch€ E. Shaping ability of ProTaper NEXT and BT-RaCe nickel–titanium instruments in severely curved root canals. International Endodontic Journal. Aim To compare the shaping ability of four different nickel–titanium rotary instruments during the preparation of curved root canals in extracted teeth. Methodology A total of 80 root canals with curvatures ranging between 25° and 39° were divided into four groups of 20 canals. Based on radiographs taken prior to instrumentation, the groups were balanced with respect to the angle and the radius of canal curvature. Canals were prepared to a final apical size of 40 using Mtwo, ProTaper Universal, ProTaper NEXT and BT-RaCe. Using pre- and postinstrumentation radiographs, straightening of the canal curvatures and canal transportation were determined with a computer image Analysis Programme. Preparation time and instrument failures were also recorded. The data were analysed statistically using ANOVA and Student–Newman–Keuls test. Results The use of BT-RaCe files resulted in significantly more straightening during instrumentation compared to Mtwo (P 0.05). No significant differences were obtained between all four instruments regarding canal transportation (P = 0.429). Instrumentation with ProTaper NEXT files was significantly faster than with all other instruments (P 0.05). Conclusions Within the parameters of this study, all instruments maintained root canal curvature well and were safe. However, care should be taken when using the BT2 instrument due to its unique cylindrical design.

  • shaping ability of different single file systems in severely curved root canals of extracted teeth
    International Endodontic Journal, 2013
    Co-Authors: Sebastian Burklein, S Benten, Edgar Schafer
    Abstract:

    Aim To compare the shaping ability of three different single-file systems with Mtwo rotary instruments during the preparation of curved root canals in extracted teeth. Methodology A total of 80 root canals with curvatures ranging between 25° and 35° were divided into four groups of 20 canals. Based on radiographs taken prior to instrumentation, the groups were balanced with respect to the angle and the radius of canal curvature. Canals were prepared to the following apical sizes: Mtwo: size 30 using the single-length technique; Reciproc, F360, and OneShape: size 25. Using pre- and post-instrumentation radiographs, straightening of the canal curvatures was determined with a computer image Analysis Programme. Preparation time, changes in working length, and instrument failures were also recorded. These data were analysed statistically using anova and Student–Newman–Keuls test. Results During preparation, no file fractured. All instruments maintained the original canal curvature well with no significant differences between the instrument systems (P = 0.792). Instrumentation with Reciproc and OneShape was significantly faster than with F360 and Mtwo (P < 0.05), while F360 was significantly faster than Mtwo (P < 0.05). No significant differences were obtained regarding changes in working length during instrumentation with the different instruments (P = 0.784). Conclusions Under the conditions of this study, all instruments respected the original canal curvature well and were safe to use. The use of Reciproc and OneShape instruments required less time to prepare the curved canals compared with Mtwo and F360.

Leesa Lin - One of the best experts on this subject based on the ideXlab platform.

  • assessment of public attention risk perception emotional and behavioural responses to the covid 19 outbreak social media surveillance in china
    medRxiv, 2020
    Co-Authors: Zhiyuan Hou, Hao Jiang, Xinyu Zhou, Leesa Lin
    Abstract:

    Background: Using social media surveillance data, this study aimed to assess public attention and awareness, risk perception, emotion, and behavioural response to the COVID-19 outbreak in real time. Methods: We collected social media data from the three most popular platforms in China: Sina Weibo (microblog), Baidu search engine, and Ali e-commerce marketplace, from the beginning of the outbreak, 1 Dec 2019, to 15 Feb 2020. Quantitative behavioural data including Weibo post counts, Weibo Hot Search ranking, and Baidu searches were used to generate indices assessing public attention and awareness. Public intention and actual adoption of recommended personal protection measures (e.g. hand sanitisers) or panic buying triggered by rumours and misinformation (e.g. garlics) were measured by Baidu and Ali indices. Correlation Analysis was performed to detect consistency among the three indices. Qualitative data from Weibo posts were collected and analysed by the Linguistic Inquiry and Word Count (LIWC) text Analysis Programme to assess public emotion responses to epidemiological events, governments’ announcements, and epidemic control measures. Findings: We identified two missed windows of opportunity for early epidemic control during the early stages of the COVID-19 outbreak, one in Dec 2019 and the other between 31 Dec and 19 Jan, when public attention and awareness was very low despite the emerging outbreak. Delayed release of information ignited negative public emotions. The public responded quickly to government announcements and adopted recommended behaviours according to issued guidelines. We found rumours and misinformation regarding remedies and cures led to panic buying during the outbreak, and timely clarification of rumours effectively reduced irrational behaviour. Interpretation: Social media surveillance can enable timely assessments of public reaction to risk communication and epidemic control measures, and the immediate clarification of rumours. This should be fully incorporated into epidemic preparedness and response systems. Funding Statement: Z.H. acknowledges financial support from the National Natural Science Foundation of China (No. 71874034) Declaration of Interests: The authors have no conflict of interest. Ethics Approval Statement: All data are publicly available.

Lin Leesa - One of the best experts on this subject based on the ideXlab platform.

  • Assessment of public attention, risk perception, emotional and behavioural responses to the COVID-19 outbreak: social media surveillance in China
    'Cold Spring Harbor Laboratory', 2020
    Co-Authors: Hou Zhiyuan, Du Fanxing, Jiang Hao, Zhou Xinyu, Lin Leesa
    Abstract:

    SummaryBackgroundUsing social media surveillance data, this study aimed to assess public attention, risk perception, emotion, and behavioural response to the COVID-19 outbreak in real time.MethodsWe collected data from most popular social medias: Sina Weibo, Baidu search engine, and Ali e-commerce marketplace, from 1 Dec 2019 to 15 Feb 2020. Weibo post counts and Baidu searches were used to generate indices assessing public attention. Public intention and actual adoption of recommended protection measures or panic buying triggered by rumours and misinformation were measured by Baidu and Ali indices. Qualitative Weibo posts were analysed by the Linguistic Inquiry and Word Count text Analysis Programme to assess public emotion responses to epidemiological events, governments’ announcements, and control measures.FindingsWe identified two missed windows of opportunity for early epidemic control of the COVID-19 outbreak, one in Dec 2019 and the other between 31 Dec and 19 Jan, when public attention was very low despite the emerging outbreak. Delayed release of information ignited negative public emotions. The public responded quickly to government announcements and adopted recommended behaviours according to issued guidelines. We found rumours and misinformation regarding remedies and cures led to panic buying during the outbreak, and timely clarification of rumours effectively reduced irrational behaviour.InterpretationSocial media surveillance can enable timely assessments of public reaction to risk communication and epidemic control measures, and the immediate clarification of rumours. This should be fully incorporated into epidemic preparedness and response systems.FundingNational Natural Science Foundation of China.

I.f. De ,coo - One of the best experts on this subject based on the ideXlab platform.

  • Cluster headache: Clinical aspects and therapy with neurostimulation
    2020
    Co-Authors: I.f. De ,coo
    Abstract:

    This thesis provides an insight in the clinical aspects and therapy with neurostimulation in cluster headache patients. An unique cohort of Dutch cluster headache patients (LUCA - Leiden University Cluster headache neuro-Analysis Programme) has been used to analyse different clinical aspects like drug-use, chronobiology and aura symptoms in cluster headache patients. Regarding neuromodulation: a case-report about occipital nerve stimulation and pregnancy is described here and a meta-Analysis of non-invasive vagal nerve stimulation as acute treatment in both episodic and chronic cluster headache

  • Cluster headache: Clinical aspects and therapy with neurostimulation
    2020
    Co-Authors: I.f. De ,coo
    Abstract:

    This thesis provides an insight in the clinical aspects and therapy with neurostimulation in cluster headache patients. An unique cohort of Dutch cluster headache patients (LUCA - Leiden University Cluster headache neuro-Analysis Programme) has been used to analyse different clinical aspects like drug-use, chronobiology and aura symptoms in cluster headache patients. Regarding neuromodulation: a case-report about occipital nerve stimulation and pregnancy is described here and a meta-Analysis of non-invasive vagal nerve stimulation as acute treatment in both episodic and chronic cluster headache. Nederlandse Hoofdpijn Vereniging (NHV)LUMC / Geneeskund